Chemistry of inorganic compounds – Nitrogen or compound thereof – Oxygen containing
Patent
1996-02-02
1997-11-04
Langel, Wayne
Chemistry of inorganic compounds
Nitrogen or compound thereof
Oxygen containing
534552, 534556, 534569, 570206, C01B 2124
Patent
active
056836686
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the generation of nitric oxide gas using solid complexes of nitric oxide, in particular zwitterionic polyamine-nitric oxide adducts.
BACKGROUND OF THE INVENTION
Nitric oxide (NO) has many important uses in biological, pharmaceutical, chemical, and industrial applications. For example, NO is a key bioregulatory molecule that plays critical roles in the regulation of various biological processes, including the normal physiological control of blood pressure, macrophage-induced cytostasis and cytotoxicity, inhibition of platelet aggregation, and neurotransmission (Moncada et al., Pharmacological Reviews, 43(2), 109-142 (1991)). Many diseases, such as endotoxic shock, ischemia reperfusion injury, genetic mutations, cancer, male impotence, and atherosclerosis have been suggested to be caused by defects in the production and/or regulation of NO (Moncada et al., supra; Masini et al., Agents and Action, 33, 53-56 (1991)). The use of NO-releasing compounds in the treatment of hypertension and other cardiovascular disorders is disclosed in U.S. Pat. No. 4,954,526, which corresponds to WO 92/05149, U.S. Pat. Nos. 5,039,705, and 5,155,137.
In addition to its role as an important bioeffector molecule, NO has many other uses, particularly in chemical and industrial applications. NO is used extensively in both the laboratory and the industrial plant. For example, NO gas is used to directly effect desired chemical results, and the NO radical is involved in the formation of diazotizing
itrosating agents, which are used to achieve a variety of chemical results.
Free NO gas is used in the preparation of nitric acid, nitrosyl chloride, metal nitrosyls, and caprolactam, which, in turn, is used in the synthesis of nylon (McCleverty, Chem. Rev., 79, 53-76 (1979)). NO gas can be used to produce aryl bromides from aryl amines by a procedure which was developed as an alternative to traditional Sandmeyer reaction (Brackman and Smit, Recl. Tray. Chim. Pays-Bas, 85, 857-864 (1966)). The NO gas is used to produce cuptic bromide nitrosyl in situ, which converts the amine to a diazonium salt and then to the bromide. NO is also used commercially as a polymerization inhibitor during the preparation of olefins (U.S. Pat. No. 4,040,912 and French Patent 2,478,648) and to improve the properties of various polymers (German Patent 2,216,844). There are numerous other potential chemical and industrial uses of NO, such as the synthesis of dyes via diazonium salts (Brackman and Smit, supra).
The potential uses of NO undoubtedly have been limited by the fact that NO is a highly poisonous and reactive gas. It is a strong irritant to the skin and mucous membranes. Moreover, NO is difficult to store in compact form, has a boiling point of -152.degree. C., and is dangerous to transport. Also, NO gas cannot be manipulated in the presence of oxygen and will attack most metals and plastics. Consequently, NO is a difficult gas to handle, and the constraints on its use are compounded by the fact that, generally, NO can only be purchased in relatively low-pressure cylinders, thereby making its storage and distribution quite cumbersome and relatively expensive.
Currently, NO is either prepared on-site or shipped in heavy stainless steel cylinders at a pressure of 500 psig. When prepared on site, sodium nitrite, which serves as the source of NO, is reacted with acidified iron sulfate to release NO gas, which then must be purified to remove higher oxides of nitrogen (Blanchard, Inorg. Synth., 2, 126-128 (1946)). The method employs a rather large apparatus to contain the slurry of salts used in the reaction and to ensure that pure NO gas is obtained. This process suffers from several disadvantages, including the production of large volumes of highly acidic (H.sub.2 SO.sub.4), iron-containing waste and concentrated alkaline waste, given that NaOH is used to remove NO.sub.2 from the gas before use, and the inability to turn the gas generation on or off as desired.
The literature is replete with
REFERENCES:
patent: 4256462 (1981-03-01), Frank et al.
patent: 4303419 (1981-12-01), Frank et al.
patent: 5155137 (1992-10-01), Keefer et al.
Maragos et al. "Complexes of .sup..cndot. NO with Nucleophiles as Agents for the Controlled Biological Release of Nitric Oxide Vasorelaxant Effects" Apr. 3, 1991. pp. 3242-3247, Journal of Medicinal Chemistry vol. 34.
Hrabie Joseph A.
Keefer Larry K.
Langel Wayne
The United States of America as represented by the Department of
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